Compute the Mean and Standard Deviation of a Binomial Random Variable
-A quiz consists of 190 true or false questions. If the student guesses on each question, what is the mean number of correct answers
A) 95
B) 0
C) 190
D) 38

Question

Quizplus · Accepted Answer

The mean ($\mu$) of a binomial distribution is given by $\mu = np$, where $n$ is the number of trials (in this case, 190 questions) and $p$ is the probability of success on each trial (for a true or false question, $p = 0.5$). Thus, $\mu = 190 \times 0.5 = 95$.